Means for cutting hard construction materials



R. MEIER March 17, 1970 MEANS FOR CUTTING HARD CONSTRUCTIQN MATERIALS Filed Nov. 4, 1968 III/g INVENTOR. 0 r W52 United States Patent Office 3,500,774 Patented Mar. 17, 1970 3,500,774 MEANS FOR CU'I'IING HARD CONSTRUCTION MATERIALS Robert Meier, Seestrasse 158, Kusnacht, Zurich, Switzerland Continuation-impart of application Ser. No. 724,016,

Apr. 25, 1968. This application Nov. 4, 1968, Ser.

Int. Cl. F23b 7/00; F23d 21/00 US. Cl. 110-1 3 Claims ABSTRACT OF THE DISCLOSURE A torch constructed as tube of steel, iron and the like material having therein fastened lengthwise weldable wires. Oxygen is passed through the tube and wires, whereby the ignited tube burns away at its end and the resulting heat burns holes according to melting process in hard materials such as concrete, rock, cast iron and the'like. A feature is that the tube has at least one annular groove which extends into the interior of the tube and by contracting acts clampingly on the wires and gives a reduction of the cross section for the flow of oxygen.

This invention is a continuation-in-part of the application of Robert Meier, Ser. No. 724,016, filed Apr. 25, 1968 for Means for Cutting Hard Construction Materials.

The present invention concerns burners for burning holes in concrete, rock, cast iron or other materials of hard structure, which consist of a tubular steel or iron envelope in which wires of weldable material are inserted and through which oxygen flows and is burned at one end.

In the burning of holes with such a burner the tube is slowly rotated and lightly struck against the material of hard structure. In order that the wires do not change their positions in the envelope and the flow of oxygen between the wires and through the tube always remains the same, it is important to secure these wires to the tubular envelope.

For this purpose it has already been proposed to strike separate indentations into the outer tube from outside, which exert lateral pressure on the wires, and to press a cylindrical tube into a tn'angular cross section after the insertion of the wires. A further proposal is to bend the wires one or more times before insertion into the tube,

so that they lock one another laterally in the tube. These methods of securing on the one hand are too little under control and on the other hand are complicated and expensive to achieve.

To overcome these disadvantages, a burner in accordance with the present invention comprises a burner for burning holes in materials of hard structure such as concrete, rock, cast iron and the like, comprising a cylindrical metal tube having weldable wires extending longitudinally therein, said tube having at least one annular groove which acts as a constriction in the interior of the tube and clamps the wires in position.

Various exemplary embodiments of the invention will now be described with reference to the accompanying drawings in which:

FIGURE 1 shows an elevation of an apparatus incorporating a burner in accordance with the invention.

FIGURE 2 a cross section through the burner'tube of FIGURE 1,

FIGURE 3 shows on a larger scale an elevation partly in section of part of the burner of FIGURE 1,

FIGURE 4 shows the same view of an alternative form of burner, according to the invention, and

FIGURE 5 shows in similar view a further form of a burner according to the invention.

In FIGURE 1 are illustrated the most important parts of a known torch 10 for burning holes in concrete namely the oxygen supply pipe 12 with the regulating cock 14, the connecting and holding member 16 for the burner 18, which burner takes the form of a tube filled with longitudinal wires 20 as shown in FIGURE 2. In accordance with the invention the burner 18 has annular grooves 22 which serves for holding the wires 20 fast in the tube.

Various ways in which these grooves may be formed are illustrated in FIGURES 3-5 and the production of which is more fully described below.

In the embodiments shown in FIGURE 3, the groove 24 consists of an annular deepening produced in known manner, e.g. the lathe, by swaging, which presents knurling on its surface. For the production of this deepening, a known tool which presents three swaging rollers opposite one another, the spacing of which is decreased gradually and during the operation of rotation around the tube can be employed. The depth of the groove 24 is made so great that the inward deformation of the tube caused by the external pressure in the operation leads to a constriction 26 of the internal cross section of the tube 18 and at the same time to clamping fast of the wires 20.

In the embodiment shown in FIGURE 4, after insertion of the wires 20 in the tube 18 a heated ring 32 is drawn on to the tube which ring contracts as it cools. This so-called shrinking process, which is well known, gives rise tolarge forces which result in the formation of the groove 34 and at the same time the constriction 36 of the tube 18 and thus the clamping of the wires 20.

In the embodiment of FIGURE 5, again a ring 38 is drawn on to the tube 18. In this example, the groove 36 can be pre-turned to small depth and the ring again be drawn on hot, the shrinking not however causing any change of form of the tube enclosure. Drawing on hot only serves for the mounting of the ring 38. Actual pressing is produced by a sleeve 39 which has screw engagement 44 with the tube 18 and the end of which presents a conical widening 46. As the ring 38 cannot escape from the groove 40, it is compressed during an axial movement of the sleeve in the direction of the arrow, 'by the conical narrowing of the sleeve 39. This pressing can be continued by movement of the sleeve 39 until the wires 20 have been sufliciently clamped by the internal constriction so produced.

The sleeve can be a component of the connecting and holding member.

The burner tube can have one or more of the annular grooves described, according to its length. Preferably there are two annular grooves spaced between 8 and 15 cm. and situated near the end of the tube inserted in said supply line. Both annular grooves situated One after another cause an increased jet action of the oxygen.

In working with known burners of this type it has been found that the provision of kinks in the inserted wires or irregularity in the disposition of indentations over the whole length of the tube results in disturbed oxygen flow in the tube. This is avoided 'by the arrangement according to the invention because the internal symmetry of the tube is not affected by the annular groove. When making the annular grooves there is a reduction of the internal cross section of the tube and the core material in the interior of the tube is deformed and clustered together without resulting in a shifting of the wire material in axial direction. The result is a substantial reduction of the flow cross section for the oxygen. The best results were obtained when the flow cross section at the constricted part is 25-65%, preferably 30-50%, smaller than the normal flow cross section of the burner. Normally, oxygen pressure necessary for the working should be between 8 and 12 atii.

EXAMPLE 1 Burner comprising a A" tube packed with a core of one steel rod of D. 3.6 mm. and seven wires of 0D. 2.5 mm. placed around the steel rod. The burner has a normal fiow cross section of 21 mm. and a flow cross section of 12 mm. at the place of the constriction of 0.35 mm. depth. This means a reduction of the flow cross section of about 41%.

EXAMPLE 2 Diameter of the tube /8", core: four wires of 0D. 2.7 mm. and ten wires of 0D. 2.7 mm., depth of groove 0.5 mm. Reduction of the flow cross section from 56.0 mm. to 36.5 mm. i.e. about 35%.

The reduction of the flow cross section results in an increased jet action of the oxygen. The advantages of the described burner in comparison with known constructions are a smaller consumption of oxygen, material consumption of the burner is less and a shorter burning timeis required. Therefore, the work is carried out more economically in all respects.

What we claim is:

1. A method of making a burner for burning holes in materials of hard structure such as concrete, rock, cast iron and the like comprising the steps of inserting a plurality of weldable wires longitudinally within a cylindrical metal tube and then compressing a portion of said tube for constricting the inside diameter of said tube for causing groove means to be formed on said tube and for simultaneously clampingly holding said Wires in said tube.

2. A method of making a burner according to claim 1, wherein said tube is constricted by application of a swaging roller.

3. A method of making a burner according to claim 1, wherein said tube is constricted by heating a ring, placing the ring about said tube, and allowing said ring to cool and shrink about said tube.

References Cited UNITED STATES PATENTS 1,631,290 6/1927 Sheedy et a1. 2,210,640 8/ 1940 SwalTord. 3,260,076 7/1966 Humberg 431-99 CHARLES J. MYHRE, Primary Examiner U.S. Cl. X.R. 43199 

